connectdatabase.java

来自「JAVA数据库编程实例随书源码」· Java 代码 · 共 83 行

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import javax.servlet.*;import javax.servlet.http.*;import java.io.*;import java.util.*;import java.sql.*;import java.io.*;import javax.servlet.*;import javax.servlet.http.*;/** * Title:        建立Servlet小应用程序与student.gdb数据库的连接 * Description:  Java语言演示程序:建立Servlet小应用程序与student.gdb数据库的连接,用于北京师范大学计算机系Java课程教学示范。 * Copyright:    Copyright (c) 2002 * Company:      北京师范大学计算机系 * @author 孙一林 * @version 1.0 */public class ConnectDatabase extends HttpServlet{	/** 建立Servlet与数据库的连接并通过SQL命令获取数据库数据*/	public void service(HttpServletRequest request, HttpServletResponse response)		throws ServletException, IOException{		PrintWriter	out;		String		title = "Servlet建立与数据库的连接";		response.setContentType("text/html;charset=GB2312");		out = response.getWriter();		out.println("<HTML><HEAD><TITLE>");		out.println(title);		out.println("</TITLE></HEAD><BODY>");		out.println("<H1>" + title + "</H1>");		out.println("<P>这是从Servlet输出的数据库数据");		String driverName = "interbase.interclient.Driver";                Driver d;		Connection con;		Statement stmt;		ResultSet results;		try {			d = (Driver)Class.forName(driverName).newInstance();			con = DriverManager.getConnection("jdbc:interbase:testdb.gdb","SYSDBA","masterkey");			stmt = con.createStatement();			String sqlstr = "select * from test";			results = stmt.executeQuery(sqlstr);	// 获取数据库结果集			displayResult(results,out);			// 输出为HTML显示格式			stmt.close();			con.close();		}		catch (Exception e) {			out.println("错误:" + e.toString());		}		out.println("</BODY></HTML>");		out.close();	}	/** 在Web页面中显示数据库数据*/	public void displayResult(ResultSet results,PrintWriter out){		StringBuffer buf = new StringBuffer();		String temp;		try {			ResultSetMetaData rsmd = results.getMetaData();			int numCols = rsmd.getColumnCount();			int i, rowcount = 0;			for (i=1; i <= numCols; i++){			if (i > 1) buf.append(",");				buf.append(rsmd.getColumnLabel(i));		}		buf.append("\n");		while (results.next() && rowcount < 100){			for (i=1; i <= numCols; i++) {				if (i > 1) buf.append(",");					buf.append((results.getString(i)));			}			buf.append("<br>");			rowcount++;		}		out.println("<br>");		out.println(buf.toString());		results.close();       		} catch (Exception e) {			out.println("错误:" + e.toString());			return;		}	}}

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